JP6045597B2 - Solid state lighting module with improved heat spreader - Google Patents

Description

  The present invention relates to a solid state lighting module for rotational mounting to a socket and a socket for housing such a solid state lighting module.

  Solid state lighting is used in many different applications in different fields. Light emitting diodes (LEDs) are an example of a solid state light source that is often used in everyday lighting.

  One of the main advantages of solid state light sources is their long lifetime, which is one reason why solid state lighting is increasingly used for lighting. The operating life of LED lamps is about 100,000 hours, 20 times longer than incandescent lamps. Even if the remaining lifetime of a solid state light source is quite long, the solid state light source can be used between different solid state light sources due to failures in individual devices or to provide different light output characteristics. It is interesting that it is possible to replace it for replacement. Therefore, module systems for solid-state lighting that allow the possibility of replacing and upgrading solid-state light sources are on the market. Such a module system includes a solid state lighting module and a socket. The solid state lighting module is attached to the socket by rotation.

  An important feature of rotating-mount solid-state lighting is the efficient dissipation of heat generated by the solid-state light source because heat reduces the life of the solid-state light source and reduces performance. This is because it can be lowered.

  It is an object of the present invention to provide improved heat dissipation between a solid state lighting module and a socket for rotational mounting.

  According to a first aspect of the present invention, this and other objects are achieved by a solid state lighting module for mounting in a socket by rotation of a solid state lighting module about a rotation axis, said solid state lighting module comprising: A heat diffusing member having a first surface and a second surface disposed in opposition to at least one solid state light source and thermally connected to each other, wherein the first surface comprises at least one solid state light source The thermal diffusion member in thermal connection with the solid state light source, and a corresponding fastening included in the socket for thermally connecting the second surface of the thermal diffusion member with a heat sink included in the socket. Fastening means arranged to cooperate with the means, wherein the second surface of the heat spreading member is relative to the axis of rotation. Qualitatively it has a surface topography with at least one peak and at least one trough arranged concentrically.

  In this context, surface topography should be understood as a change in surface structure.

  In this context, the term solid state light source should be understood as a semiconductor-based light source, for example a light emitting diode or a laser diode.

  The second surface of the heat spreading member may advantageously be substantially perpendicular to the axis of rotation described above, about which the solid state lighting module is rotated during attachment to the socket .

  The fastening means may be any type of means that can be attached by rotation. Examples include bayonet connections and threads.

  The present invention is based on the understanding that better heat conduction to the same outer periphery of the heat diffusing member can be achieved by increasing the contact area between the heat diffusing member and the heat sink. This is accomplished by providing a surface change having at least one peak and at least one valley in the heat spreading member, the surface change increasing the area of the second surface of the heat spreading member and thus. Thermally contacts the heat sink, thereby allowing an increased area of the heat spreading member that improves heat transfer from the solid state light source. The inventor further noted that this increased contact area can be achieved for a solid state lighting module for rotational mounting to a socket by providing a surface topography of the heat spreading member concentric with respect to the axis of rotation. Noticed. The surface changes are substantially equal with the same radius around the axis of rotation.

  According to one embodiment, the second surface of the heat spreading member has a surface topography having a plurality of peaks and valleys arranged substantially concentrically with respect to the axis of rotation.

  The surface change of the heat diffusing member may be a sine curve.

  According to one embodiment, the peak-to-peak amplitude between the peaks and valleys of the surface topography of the heat spreading member is at least 250 μm. If a certain desired increase in contact area is achieved, surface topography with small inter-vertex amplitude requires more peaks and valleys than surface topography with large inter-vertex amplitude. With a smaller number of peaks and valleys (and a greater distance between adjacent peaks / valleys in a direction perpendicular to the axis of rotation), the manufacturing tolerance requirements for solid state lighting modules (and sockets) are less stringent. Become. Therefore, the peak-to-peak amplitude between the peaks and valleys of the surface topography of the heat spreading member of at least 1 mm is even more advantageous.

  According to various embodiments, further, the distance between adjacent peaks and / or valleys in a direction perpendicular to the axis of rotation may be at least 0.5 mm, which increases the contact area due to manufacturing tolerances. And can be achieved with reasonable requirements of positioning tolerances.

  Furthermore, the peaks and valleys may be round. This reduces manufacturing tolerance requirements compared to the case where peaks and valleys have sharp edges. Thus, improved thermal contact between the heat spreading member and the heat sink can be achieved without substantially requiring potentially high cost precision machining.

  The peaks and valleys may be advantageously rounded with a radius of curvature of at least 0.5 mm.

  As described above, the overall increase in the contact area between the heat diffusing member of the solid state lighting module and the heat sink of the socket is mainly due to the peak-to-peak amplitude between the peaks and valleys and the frequency of the peaks and valleys. Or it depends on the density (ie the density of the pleats). For example, in the case of a surface topography with a substantially sinusoidal cross-section and a ratio of peak-to-vertex amplitude to wavelength of at least 1, the increase in contact area is greater than that with a flat thermal diffusion member. At least about 60% without increasing the space required for

  Solid state lighting modules according to various embodiments of the present invention may be advantageously designed such that the heat spreading member has several different materials and different configurations. The heat spreading member may be a metal plate, slab, or sheet that provides good thermal conductivity for effective conduction of heat generated by the solid state light source. The heat spreading member may include other materials such as metal alloys, thermal epoxies, graphite, diamond, or other carbon-based materials.

  A further advantage of using a conductive material such as metal for the heat spreader is that no additional ground contact between the solid state lighting module and the socket is required, which facilitates manufacturing, Reduce costs or increase robustness.

  A macroscopic concentric surface change of a heat spreading member for rotational mounting, for example, a surface change across the apex of 1 mm, greatly increases the heat transfer area by increasing the area of the heat spreading member that is in thermal contact with the heat sink. Improve. In addition to the macroscopic surface change, the surface of the thermal diffusion member may generally have irregularities on a micrometer scale. The irregularities include interstitial air that reduces physical contact and heat transfer between the surfaces.

  According to one embodiment of the present invention, the contact area provides a heat spreading member having a metal sheet arranged as a biasing spring that bends toward the solid state lighting module when applying pressure to the heat spreading member. This is further increased.

  In one embodiment, the heat diffusing member is disposed as a biasing spring that bends in a direction toward the solid state light source when the solid state lighting module is attached to the socket when the heat diffusing member contacts the heat sink. May be included.

  When the spring force of the sheet is overcome by the fastening means, the metal sheet is in thermal contact with the heat sink in the socket. In order for the metal sheet to substantially match the microsurface changes of the heat sink, the metal sheet must be thin enough. However, the thermal conductivity is reduced for thinner metal sheets. The appropriate thickness range depends on the material selected for the metal sheet. For aluminum, the optimum thickness range for metal sheets is 0.1-1.5 mm, and for stainless steel, the optimum thickness range is 0.05-0.3 mm. Furthermore, for copper, which can be a suitable choice of material, the optimum thickness range is 0.05-0.5 mm.

  An additional advantage of using a spring loaded metal sheet is that the metal sheet can be adjusted and adapted to any mismatch between the surface topography peaks and valleys of the heat spreader and the heat sink. It is.

  According to another embodiment, the portion of the thermal diffusion member facing away from the solid state light source may be made of a metal having a hardness of less than 60 on the Brinell hardness scale.

  Examples of such soft metals include, for example, 1000 series aluminum, tin, silver, or lead. Apart from solutions using heat conducting materials and metal sheets, the inventor further dissipated heat by using a metal having a hardness of less than 60 on the Brinell hardness scale as part of the heat spreading member adjacent to the second surface. Also noticed how to improve. The rotational mounting of the solid state lighting module to the socket effectively deforms the metal to fit the small irregularities of the heat sink.

  Rotational mounting contributes to ensure good thermal contact between the heat spreading member and the heat sink. A further advantage of this embodiment is that the rotational mounting is performed with less effort, with the adaptable surface layer of the heat diffusing member, while the heat diffusing member adapts to the minute irregularities of the heat sink to improve heat dissipation. That is.

  A further improvement in heat transfer according to one embodiment is that the second surface of the heat spreading member is at least partially covered with a heat conducting material. The thermally conductive material may be advantageously provided in the form of a paste, allowing a thermal interface to be formed around surface irregularities such as particle contamination. For example, thermal grease can be used to reduce voids in the gap air between the heat spreading member and the heat sink. Air is not a good heat conductor, so heat-conducting materials may be used as a complement to improve heat dissipation because even smooth surfaces have a small gap of air on the micrometer scale. . The layer of thermal grease can also be adjusted to reduce friction during rotational mounting.

  According to one embodiment, the second surface of the heat spreading member is arranged to at least partially cover the thermally conductive material to reduce friction during attachment of the solid state lighting module to the socket. A liner is further included on the second surface of the heat spreading member.

  The liner may be a plastic material that is arranged to create a less frictional layer for easier rotational mounting.

  According to a second aspect of the present invention there is provided a socket for receiving a solid state lighting module according to any one of the preceding claims by rotation about a rotation axis, said socket comprising: a heat sink; Arranged in cooperation with corresponding fastening means included in the solid state lighting module to thermally connect the surface of the heat sink with the second surface of the heat spreading member included in the solid state lighting module. Fastening means, the surface of the heat sink having a surface topography having at least one peak and at least one valley arranged substantially concentrically with respect to the axis of rotation. The surface changes of the heat diffusion member and the heat sink are arranged to complement each other. For example, the raised portion in the surface change of the heat diffusing member corresponds to a uniform recess in the surface change of the heat sink.

  Furthermore, the solid-state lighting module according to the first aspect of the present invention may be advantageously included in a solid-state lighting device, said solid-state lighting module being rotated around a rotation axis. Further comprising a socket for housing the heat sink and a corresponding fastening means included in the solid state lighting module, between the surface of the heat sink and the second surface of the heat spreading member. And fastening means for providing a thermal connection. The surface topography of the surface of the heat sink is substantially opposite to the surface topography of the second surface of the heat spreading member. Advantageously, the surface of the heat sink may comprise a plastic material and is therefore provided on the surface of the heat sink to substantially match the surface topography of the heat spreading member, and therefore the surface topography of the surface of the heat sink is Substantially the reverse of the surface topography of the second surface of the heat spreading member. Alternatively, the surface topography of the heat spreading member includes at least one peak and at least one valley arranged substantially concentrically with respect to the axis of rotation, wherein the peak of the heat spreading member of the solid state lighting module is: Constructed to fit the corresponding valley of the heat sink of the socket.

  It should be noted that the invention relates to all possible combinations of the features listed in the claims.

  These and other aspects of the invention will now be described in detail with reference to the accompanying drawings, which illustrate exemplary embodiments of the invention.

FIG. 1 schematically illustrates a solid state lighting device including a solid state lighting module according to an embodiment of the present invention and a socket according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of the solid state lighting device in FIG. 1 schematically illustrating a thermal connection between a heat spreading member included in the solid state lighting module and a heat sink included in the socket. . FIG. 3a illustrates two different exemplary embodiments of the thermal connection of the thermal interface between the heat spreading member and the heat sink between the heat spreading member contained in the solid state lighting module and the heat sink contained in the socket. It is one of the expanded fragmentary sectional views illustrated about. FIG. 3b illustrates two different exemplary embodiments of the thermal connection of the thermal interface between the heat spreading member and the heat sink between the heat spreading member contained in the solid state lighting module and the heat sink contained in the socket. It is one of the expanded fragmentary sectional views illustrated about. FIG. 4a is a schematic partial cross-sectional view of another embodiment of a solid state lighting module according to the present invention. FIG. 4b shows the thermal connection of the thermal interface between the heat spreading member and the heat sink between the heat spreading member contained in the solid state lighting module and the heat sink contained in the socket. It is an expanded sectional view which illustrates about further embodiment containing this.

  In the following description, the present invention will be described with respect to an LED-based light emitting device in which the LED module is attached to the socket using bayonet type fastening means.

  It should be noted that this in no way limits the scope of the invention, which is equally applicable to other solid state lighting modules including, for example, semiconductor lasers. Furthermore, the solid state lighting module may be attachable to the socket using other types of fastening means such as, for example, screw connections.

  FIG. 1 schematically illustrates a solid state lighting device 101 that includes a solid state lighting module 102 and a socket 103.

  The solid state lighting module 102 includes a printed circuit board 107, a plurality of solid state light sources in the form of light emitting diodes (LEDs) 112, a heat spreader 104, a substantially cylindrical housing 105, a reflector 108, an optically transmissive. It includes a top cover 106 and fastening means in the form of protrusions or protrusions 109 here. The LED 112 is electrically and thermally connected to the printed circuit board 107 and is thermally connected to the heat spreader 104 to dissipate the heat generated by the LED 112 during this operation. The cylindrical housing 105 and the top cover 106 are disposed so as to form a housing surrounding the LED 112, and the reflector 108 is disposed inside the housing to collimate the light emitted by the LED 112.

  The socket 103 includes a heat sink 110 and fastening means in the form of a recess 113. As schematically shown in FIG. 1, the solid state lighting module 102 inserts the protrusion 109 of the solid state lighting module 102 into the corresponding recess 113 of the socket in the axial direction so that the solid state lighting module 102 is inserted. It is attached to the socket 103 by rotating around a rotation axis 111. Due to the configuration of the protrusion 109 and the recess 113, the solid state lighting device is then secured to the socket in such a manner that the heat spreader 104 is pressed against the heat sink 110. At the same time, the LEDs are connected to the power unit via connection means (not shown in FIG. 1) included in the socket 103 for electrically connecting the LEDs 112 of the solid state lighting module 102.

  When the heat spreader 104 of the solid state lighting module 102 is pressed against the heat sink 110 of the socket 103, a thermal connection between the heat spreader 104 and the heat sink 110 is achieved. According to various embodiments of the present invention, this thermal connection is achieved by increasing the contact area between the heat spreader 104 and the heat sink 110 through appropriate surface topography of the heat spreader 104 and the heat sink 110 as compared to the prior art. Improved.

  As schematically illustrated in FIG. 1, the heat spreader 104 includes a first surface 114 facing the LED 112 and a side away from the LED 112 (and a heat sink 110 when the solid state lighting module is attached to the socket 103. And the second surface 115 facing the other side. The second surface 114 has a surface topography having a plurality of peaks 119 and valleys 120 arranged substantially concentrically with respect to the rotation axis 111. This allows for rotational mounting and increased thermal contact area when the solid state lighting module 102 is mounted in a suitable socket 103. As schematically shown in FIG. 1, such a socket 103 may have a heat sink having a surface topography that is substantially the opposite of the surface topography of the heat spreader 104 of the solid state lighting module 102. In particular, the heat sink 110 of the socket 103 of FIG. 1 has an upper surface 116 that faces toward the receiving opening of the socket 103. The top surface 116 has a surface topography having a plurality of peaks 117 and valleys 118 arranged concentrically with respect to the axis 111 of rotation in an opposite configuration compared to the peaks 119 and valleys 120 of the heat spreader 104. Alternatively, the heat sink 110 may be made of a material that is compatible with the surface topography of the heat spreader 104.

  FIG. 2, which is a schematic partial cross-sectional view of the solid-state lighting device 101 in FIG. 6 illustrates the increased thermal contact area achieved when pressed.

  Various embodiments of the solid state lighting module according to the present invention with different heat spreader configurations will now be described with reference to FIGS. 3a and 3b and FIGS. 4a and 4b.

  The surface topography with corresponding peaks and valleys of the heat spreader 104 and heat sink 110 schematically illustrated in FIGS. 1 and 2 is in thermal contact compared to a conventional configuration with a flat heat spreader pressed against a flat heat sink. Increase area. Further increases in the thermal contact area can also be achieved by processing microscale surface changes of the heat spreader 104 and / or heat sink 110, otherwise there is a minute difference between the heat spreader 104 and the heat sink 110. Will cause a hollow part.

  According to a first embodiment schematically illustrated in FIG. 3 a, a thermally conductive material 301 such as so-called thermal grease may be provided between the heat spreader 104 and the heat sink 110. This further increases the thermal contact area between the heat spreader 104 and the heat sink 110. So-called thermal greases may include a thermally conductive ceramic filler dispersed in, for example, silicon oil or hydrocarbon oil.

  According to a second embodiment schematically illustrated in FIG. 3b, the heat spreader 104 is a micro-change on the surface 116 of the (harder) heat sink 110 when the solid state lighting module 102 is attached to the socket 103 by rotation. May contain a metal that is sufficiently soft to plastically deform on a microscale. The inventor has found that a metal having a hardness of less than 60 on the Brinell hardness scale is soft enough to accommodate micro changes in the surface 116 of the heat sink 110 to achieve the desired increased thermal contact area. I found it.

  In particular, the pressure and friction between the heat spreader 104 and the heat sink 110 resulting from the rotational mounting of the solid state lighting module 102 to the socket 103 causes the metal on the second surface 115 of the heat spreader 104 to be minute on the surface 116 of the heat sink 110. Force to adapt to change. Examples of suitable metals having a hardness of less than 60 on the Brinell hardness scale include, for example, pure aluminum, tin, lead, and silver. For example, aluminum from the Al 1000 series can be used for a portion of the thermal diffusion member facing the heat sink 110.

  4a and 4b schematically illustrate a third embodiment of a solid state lighting module 102 according to the present invention. Referring to FIG. 4 a, the heat spreader 104 has a thin corrugated metal sheet that is spring loaded and biased away from the LED 112. As schematically illustrated in FIG. 4b, when the heat spreader 104 is pressed against the heat sink 110, the heat spreader adapts to micro-changes in the heat sink 110, thereby increasing the thermal contact area.

  In addition, variations of the disclosed embodiments can be understood and executed by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. . For example, the heat sink 110 contained in the socket is a thin metal fitted with a spring having a hardness of less than 60 on a Brinell scale or described above with reference to the heat spreader 104 included in the solid state lighting module 102. A metal sheet may be included.

  In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claims (10)

And Seo lid state lighting module, a solid-state lighting device comprising a socket for receiving the solid-state lighting module by rotation about the axis of rotation,
The solid state lighting module includes:
At least one solid state light source;
A heat diffusing member disposed oppositely and having a first surface and a second surface thermally connected to each other, wherein the first surface is thermally connected to the at least one solid state light source The heat diffusion member;
Fastening means for cooperating with corresponding fastening means included in the socket to thermally connect the second surface of the heat spreading member to a heat sink included in the socket;
Have
The socket is
A heat sink,
Cooperating with corresponding fastening means included in the solid state lighting module to provide thermal contact between the surface of the heat sink and the second surface of the heat spreading member included in the solid state lighting module. Fastening means;
Have
The second surface of the heat diffusing member has a surface topography having a plurality of peaks and valleys arranged substantially concentrically with respect to the rotation axis, and the surface topography of the surface of the heat sink includes the surface topography Substantially opposite to the surface topography of the second surface of the heat spreading member;
Solid state lighting device . The solid state lighting device according to claim 1 , wherein a distance between adjacent peaks and / or valleys in a direction perpendicular to the axis of rotation is at least 0.5 mm. 3. The solid state lighting device according to claim 1, wherein an amplitude between the peaks between the peaks and the valleys is at least 250 μm. The mountain and each of the valleys, are rounded, solid-state lighting device according to any one of claims 1 to 3. The solid state lighting device of claim 4 , wherein each of the peaks and valleys has a radius of curvature of at least 0.5 mm. The portion of the thermal diffusion member facing away from the solid state light source is made of a metal having a hardness of less than 60 in the Brinell hardness scale, solid state according to any one of claims 1 to 5 Lighting device . The heat diffusion member is a biasing spring that bends in a direction toward the solid state light source when the heat diffusion member is brought into contact with the heat sink included in the socket when the solid state lighting module is attached to the socket. with metal sheets arranged as, solid-state lighting device according to any one of claims 1 to 5. The second surface thermally conductive material is at least partially covered, solid-state lighting device according to any one of claims 1 to 7 of the heat diffusion member. During the mounting of the solid state lighting module to the socket, a heat spreading member that at least partially covers the heat conducting material to reduce friction between the heat spreading member and the heat sink contained in the socket. The solid state lighting device of claim 8 , further comprising a liner on the second surface. Wherein the surface of said heat sink comprises a thermoplastic material, solid-state lighting device according to claim 1.

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